WO2010035652A1

WO2010035652A1 - Data receiving terminal, data distribution server, data distribution system, and data distribution method

Info

Publication number: WO2010035652A1
Application number: PCT/JP2009/066023
Authority: WO
Inventors: 英俊上野; 亮北原
Original assignee: 株式会社エヌ・ティ・ティ・ドコモ
Priority date: 2008-09-26
Filing date: 2009-09-14
Publication date: 2010-04-01
Also published as: RU2502222C2; EP2341709A1; CN102165800A; KR20110052716A; BRPI0919028A2; US20110237180A1; KR101267245B1; PE20110915A1; CN102165800B; RU2011116401A; JP2010081397A

Abstract

A data receiving terminal (20) has a broadcast wave receiving function and a communication wave sending/receiving function. A communication control unit (210) receives data from a data distribution server (10) by using the broadcast wave receiving function. When a determination unit (220) determines that there is a defect portion, the determination unit (220) determines whether or not the defect portion should be recovered on the basis of at least one of the communication situation between the data receiving terminal (20) and the data distribution server (10) and the data relevant situation which is a situation relevant to data. When the determination unit (220) determines that the defect portion should be recovered, the communication control unit (210) requests the data distribution server (10) to resend the defect portion by using the communication wave sending/receiving function and receives the defect portion sent from the data distribution server (10) according to the request for resending by using the communication wave sending/receiving function.

Description

Data receiving terminal, data distribution server, data distribution system, and data distribution method

The present invention relates to a data receiving terminal, a data distribution server, a data distribution system, and a data distribution method.

In recent years, there are a number of services that make it possible for mobile terminals such as mobile phones and PHS to download and use various types of digital data (hereinafter referred to as “data”) such as images, sounds, moving images, and texts. . For example, a service that downloads data such as a ringing melody or wallpaper to a mobile terminal and uses the data, and a service that downloads video data such as a movie or sound data such as music to the mobile terminal and uses the data are examples. In the above service, a data receiving terminal can download and use various data from a data distribution server by using a mobile communication network such as a third generation mobile communication network (UMTS: “Universal Mobile Telecommunications System”). For downloading various data, unicast communication that distributes data in response to a request from a receiving terminal is often used.

In unicast type communication, communication occurs in response to a download start request from a data receiving terminal, so that the required communication amount relatively increases according to the number of data receiving terminals and the data amount. Accordingly, when the number of data receiving terminals and the amount of data increase, communication exceeding the capacity of the network occurs, and in some cases, problems such as inability to distribute data may occur.

On the other hand, so-called One Seg (see Non-Patent Document 1), which started service in Japan in 2006, distributes moving images, sound, and data such as text and still images to mobile terminals such as mobile phones. Service. One Seg uses a method of digital terrestrial television broadcasting called ISDB-T, and uses a broadcasting network for data distribution. In data distribution using a broadcast network, a broadcast type distribution method that distributes data simultaneously to an unspecified number of data receiving terminals is adopted.

The broadcast distribution method is characterized in that the communication volume is constant without depending on the number of data receiving terminals by simultaneously receiving radio waves for data distribution by a plurality of terminals. From the above, the broadcast-type delivery method is an effective method for delivering a large volume of data to a large number of data receiving terminals.

On the other hand, in the broadcast-type distribution method, there are many cases where there is no upstream communication path from the data receiving terminal to the data distribution server, and it is not possible to confirm delivery of whether the distribution data has reached the data receiving terminal. There are many. Therefore, there is a problem that it cannot be guaranteed whether the data has reached the data receiving terminal. On the other hand, in unicast-type data distribution, since it is a normal usage method to perform delivery confirmation using the uplink communication path while receiving data, the data is surely delivered to the data receiving terminal. It is an effective data communication method when you want to. From the above, the characteristics of the unicast data distribution method and the broadcast data distribution method can be utilized by properly using them according to their applications.

MBMS (Multimedia Broadcast Multicast Service, see Non-Patent Document 2) is a system that realizes broadcast delivery on mobile communication networks and multicast delivery that expands it and delivers data to an unspecified number of data receiving terminals. Exists. Since MBMS distributes data using a mobile communication network, it is possible to use uplink communication at the same time. Therefore, in MBMS, a reception reporting procedure (ReceptionReporting Procedure) is prepared, and it is possible to confirm whether or not distribution data has been received at the data receiving terminal. If the data receiving terminal cannot receive all the data by broadcast distribution, the missing data can be supplemented by unicast communication by the file repair procedure (FileRepair Procedure). By using the file restoration procedure, it is possible to supplement the missing files, which was a problem at the time of broadcasting wave data distribution, with unicast, so that it is possible to increase the reliability of data distribution. .

Also, as a data distribution service for next-generation mobile terminals following One Seg, a multimedia broadcasting service for mobile terminals (hereinafter referred to as “multimedia broadcasting”) is attracting attention. As of July 2008, this multimedia broadcasting is currently under discussion at the “Social Meeting on the Ideal State of Multimedia Broadcasting Services for Mobile Terminals” by the Ministry of Internal Affairs and Communications in Japan (see Non-Patent Document 3). Multimedia broadcasting is a service that is realized by using a frequency that can be newly used in accordance with digital transition of terrestrial television broadcasting stopped in Japan in 2011. Multimedia broadcasting is planned to be able to provide various combinations of video and audio data. As of July 2008, the multimedia broadcasting implementation method is under discussion in the Japanese Ministry of Internal Affairs and Communications, but the MediaFLO method (see Non-Patent Document 4) and the ISDB-Tmm method, which is an extension of the one-segment method, are proposed. Has been.

In multimedia broadcasting, a mobile phone or the like is assumed as a target data receiving terminal. Therefore, both a broadcast wave that can be newly used by frequency allocation and a mobile communication network that has been available so far can be used. There is a feature that it is possible. As a result, for example, distribution data is distributed to data receiving terminals using broadcast waves, and a mobile communication network is used for the purpose of complementing missing file data, providing functions equivalent to MBMS file restoration procedures. Is possible.

For multimedia data such as audio and video, there are two types of distribution: real-time distribution that the user views while downloading data, and download distribution that starts playback after waiting for the user's request after the data is once stored in the terminal. There are types. However, even in the case of download-type distribution, there is a form of progressive download that starts reproduction while data is being downloaded. The MBMS file repair procedure described above is a data distribution method used for download distribution.

In multimedia broadcasting, two types of distribution methods, real-time distribution and download distribution, can be used separately. For example, real-time distribution is used when distributing data with high real-time properties such as World Cup soccer broadcasts, and download-type distribution can be used for data distribution with low real-time properties such as movies and comedy programs.

When it is possible to use broadcast distribution and unicast distribution separately on a single data reception terminal, such as multimedia broadcasting and MBMS, broadcast distribution and unicast distribution are performed from the viewpoint of avoiding unnecessary communication costs. It is necessary to carefully consider and deal with how to switch between cast delivery and data download.

Therefore, the present invention has been made in view of the above, and a data receiving terminal, a data distribution server, and the like that are capable of not generating unnecessary communication costs when repairing a missing portion in data communication by a broadcast wave with a communication wave, An object is to provide a data distribution system and a data distribution method.

As a result of earnest research to achieve the above object, the present inventor generates useless communication costs when repairing a deficient part in data communication (broadcast distribution) using broadcast waves by communication waves (unicast distribution). In order not to make it happen, it was necessary to carefully consider the following issues and find an effective method.

First, there is a problem of “delivery time zone”. For example, in the case of a mobile communication network, there is a limit to the upper limit of available communication network resources, so there is a limit to unicast distribution of a large amount of data to a large number of users. In particular, in a time zone with a large traffic volume (for example, from evening to night), it is important to prevent unicast traffic having a large impact on the network as much as possible. From the above, it is necessary to devise a file restoration procedure by unicast such that it is performed in a time zone with little traffic (for example, midnight) while avoiding a time zone with a lot of traffic as much as possible.

Second, there is a problem of “type of network to be used”. In recent mobile terminals, in addition to the networks such as the above-mentioned third generation mobile communication networks, there are fixed users such as wireless LAN (W-LAN), WiMAX, and lower communication costs, and users such as Femto BTS. There are cases where a limited number of communication networks (base stations) are available. When such a network with a low communication cost is available, the influence on the traffic to the network by performing the file restoration procedure by unicast becomes relatively low. In view of the above, it is necessary to devise, for example, a file restoration procedure using a network with low communication cost as much as possible.

Third, there is a problem of “selection of target data for file restoration”. In download-type file distribution assumed in multimedia broadcasting, a download method is assumed in which all data is stored in advance in a data receiving terminal regardless of whether or not the user uses data. This has the advantage that the waiting time for communication is unnecessary because the data is already stored in the data receiving terminal when the user wants to use the data. However, in order to store all data in the receiving terminal in advance, it is necessary to repair the missing data in advance. Note that unicast is often used because unicast is suitable for reliably restoring missing data. Since this file repair procedure is performed regardless of whether the data is actually used by the user, the communication performed by the file repair procedure may actually be wasted. Therefore, it is necessary to devise how to determine data for executing the file repair procedure and which part of the entire data is to be repaired.

In the present invention, in order to solve the above three problems, in order to prevent unnecessary communication costs due to unicast when supplementing data lost after broadcast distribution by the unicast method, the following conditions are satisfied. Provide a method to compensate for missing data only if
1) When the time is low in traffic 2) When connected to a network with relatively low cost 3) When there is a high probability that the data (whole or partial) will be used from past usage history

That is, the data receiving terminal of the present invention is a data receiving terminal having a broadcast wave receiving function and a communication wave transmitting / receiving function, and a broadcast wave receiving means for receiving data from a data distribution server using the broadcast wave receiving function. Determining whether or not there is a missing part in the data, and if it is determined that there is the missing part, the communication status between the data receiving terminal and the data distribution server, and the situation related to the data Based on at least one of certain data-related situations, a repair determining unit that determines whether or not to repair the missing portion, and the communication wave transmission / reception function when the repair determining unit determines to repair the missing portion Is used to request the data distribution server to retransmit the missing portion, and is transmitted from the data distribution server based on the retransmission request. Wherein for the communication wave sending and receiving means for the lost portion is received by using the communication wave sending and receiving function, a storing means for storing the defect portion where the communication wave transmitting and receiving means has received, comprising: a being.

The data distribution server of the present invention is a data distribution server having a broadcast wave transmission function and a communication wave transmission / reception function, and uses the broadcast wave transmission function to transmit data to a data receiving terminal; Retransmission request receiving means required to retransmit the missing portion of the data from the data receiving terminal using the communication wave transmission / reception function, and based on the retransmission request, the lost portion is communicated to the data receiving terminal. And deficient part transmission means for transmitting using a wave transmission / reception function.

The data distribution system of the present invention is a data distribution system including a data receiving terminal having a broadcast wave reception function and a communication wave transmission / reception function, and a data distribution server having a broadcast wave transmission function and a communication wave transmission / reception function. The data receiving terminal uses the broadcast wave receiving function to determine broadcast wave receiving means for receiving data from the data distribution server and whether or not the data has a missing part, and the missing part is present. Whether or not to repair the missing portion based on at least one of a communication status between the data receiving terminal and the data distribution server and a data related status that is a status related to the data. A repair determining means for determining whether or not the repair determination means determines that the missing portion is to be repaired. Communication wave transmission / reception requesting the data distribution server to retransmit the missing portion and receiving the missing portion transmitted from the data distribution server based on the retransmission request using the communication wave transmitting / receiving function. And data for transmitting the data to the data receiving terminal using the broadcast wave transmission function, the data distribution server using the broadcast wave transmission function. Using the transmission means, the communication wave transmission / reception function, the retransmission request receiving means requested to retransmit the missing portion of the data from the data receiving terminal, and based on the retransmission request, the data receiving terminal And deficient portion transmitting means for transmitting the deficient portion using the communication wave transmitting / receiving function.

The data distribution method of the present invention is a data distribution in a data distribution system including a data receiving terminal having a broadcast wave reception function and a communication wave transmission / reception function, and a data distribution server having a broadcast wave transmission function and a communication wave transmission / reception function. A data transmission step in which the data transmission means of the data distribution server transmits data to the data reception terminal using the broadcast wave transmission function, and the broadcast wave reception means of the data reception terminal A broadcast wave receiving step for receiving the data from the data distribution server using a broadcast wave receiving function, and a repair determining means of the data receiving terminal determine whether the data has a missing portion, and If it is determined that there is a portion, the communication status between the data receiving terminal and the data distribution server, and the data A repair determination step for determining whether or not to repair the missing portion based on at least one of the data-related situations, which is a situation related to the data, and the communication wave transmitting / receiving means of the data receiving terminal, A first communication wave transmission / reception step for requesting the data distribution server to retransmit the defective portion when the communication wave transmission / reception function is determined to be repaired; and a retransmission request of the data distribution server Receiving means is requested to retransmit the missing portion of the data from the data receiving terminal using the communication wave transmission / reception function, and the missing portion transmitting means of the data distribution server includes: Based on a retransmission request, a missing portion transmission step of transmitting the missing portion to the data receiving terminal using the communication wave transmission / reception function; A second communication wave transmission / reception step in which the communication wave transmission / reception means of the data reception terminal receives the lost portion transmitted from the data distribution server based on the retransmission request using the communication wave transmission / reception function; and the data reception A data distribution method comprising: a storage step in which a storage unit of the terminal stores the missing portion received by the communication wave transmission / reception unit;

According to such a data reception terminal, data distribution server, data distribution system, and data distribution method of the present invention, when the data reception terminal determines that there is a missing portion in the distribution data, the data reception terminal and the data It is determined whether or not to repair the missing portion based on at least one of a communication status with the distribution server and a data related status that is a status related to the distribution data. Since it is properly determined whether or not to perform the defect repair process based on the communication status and the data-related status, wasteful communication costs can be reduced when repairing the missing portion in data communication using broadcast waves with a communication wave. It becomes possible not to generate.

In the data receiving terminal of the present invention, the communication status is a relationship between a current time and a preset time zone, and the repair determining means compares the current time with the time zone. Preferably, when the current time is within the time zone, it is determined to repair the missing portion.

In the data distribution method of the present invention, the communication status is a relationship between a current time and a preset time zone, and the repair determination means compares the current time with the time zone. Preferably, when the current time is within the time zone, it is determined to repair the missing portion.

This invention provides a measure against the problem of “delivery time zone” which is the first problem. According to the present invention, it is possible to make a condition determination for a time zone during which the file repair procedure may be executed and a time zone when the file repair procedure should not be executed, and the execution of the file repair procedure during a time zone in which network traffic is concentrated Can be prevented.

Further, in the data receiving terminal of the present invention, the communication status is a relationship between a network type currently available between the data receiving terminal and the data distribution server and a preset network type. Yes, the repair determining means compares the currently available network type with the preset network type, and determines that the missing portion is repaired if there is a match in both types. It is preferable.

Further, in the data distribution method of the present invention, the communication status is a relationship between a network type currently available between the data receiving terminal and the data distribution server, and a preset network type. Yes, the repair determining means compares the currently available network type with the preset network type, and determines that the missing portion is repaired if there is a match in both types. It is preferable.

This invention provides a countermeasure against the problem of “type of network to be used” which is the second problem. According to the present invention, it is possible to determine conditions for a network that may execute a file repair procedure and a network that should not be performed, and it is possible to execute a file repair procedure using a network with a lower communication cost. It becomes.

Further, in the data receiving terminal of the present invention, the communication status includes the types of base stations that are currently available in the currently available network, and types of base stations that are preset in relation to the currently available network. The repair determination means compares the currently available base station type and the preset base station type, and if there is a match between both types, It is preferable to determine that the defective portion is repaired.

Further, in the data distribution method of the present invention, the communication status includes the types of base stations that are currently available in the currently available network and the types of base stations that are preset in relation to the currently available network. The repair determination means compares the currently available base station type and the preset base station type, and if there is a match between both types, It is preferable to determine that the defective portion is repaired.

This invention provides a countermeasure against the problem of “type of network to be used” which is the second problem. According to the present invention, a network and a base station that can execute a file restoration procedure and a condition determination for a network and a base station that should not be executed can be performed, and a network and a base station with lower communication costs are used. It is possible to execute a file repair procedure.

In the data receiving terminal of the present invention, the communication status is a relationship between a remaining battery level of the data receiving terminal and a preset remaining battery level threshold value, and the restoration determining means It is preferable that the remaining battery level of the receiving terminal is compared with the threshold value, and it is determined that the missing portion is repaired when the remaining battery level of the data receiving terminal is equal to or greater than the threshold value.

Further, in the data distribution method of the present invention, the communication status is a relationship between a remaining battery level of the data receiving terminal and a preset remaining battery level threshold, and the restoration determining means It is preferable that the remaining battery level of the receiving terminal is compared with the threshold value, and it is determined that the missing portion is repaired when the remaining battery level of the data receiving terminal is equal to or greater than the threshold value.

According to the present invention, by considering the remaining battery level of the data receiving terminal 20 as a condition, for example, when the remaining battery level is low, it is possible to prevent the battery from running out by performing the download.

Further, in the data receiving terminal of the present invention, the communication status includes a network usage contract type currently concluded between the data receiving terminal and the data distribution server, and a preset network usage contract type. The repair determination means compares the type of the network usage contract that has been concluded with the type of the network usage contract that has been set in advance, and the type that matches between the two types In some cases, it is preferable to determine that the defect portion is to be repaired.

Further, in the data distribution method of the present invention, the communication status includes a network usage contract type currently concluded between the data receiving terminal and the data distribution server, and a preset network usage contract type. The repair determination means compares the type of the network usage contract that has been concluded with the type of the network usage contract that has been set in advance, and the type that matches between the two types In some cases, it is preferable to determine that the defect portion is to be repaired.

According to the present invention, it is possible to prevent an unexpectedly high communication fee from being generated by considering the type of network usage contract between the data receiving terminal 20 and the data distribution server 10 as a condition.

In the data receiving terminal of the present invention, the communication status is a relationship between a radio wave intensity between the data receiving terminal and the data distribution server and a preset radio wave intensity threshold, and the restoration The judging means compares the radio field intensity between the data receiving terminal and the data distribution server with the threshold value, and the radio field intensity between the data receiving terminal and the data distribution server is equal to or greater than the threshold value. It is preferable that the defect portion is determined to be repaired.

In the data distribution method of the present invention, the communication status is a relationship between a radio wave intensity between the data receiving terminal and the data distribution server and a preset radio wave intensity threshold, and the restoration The judging means compares the radio field intensity between the data receiving terminal and the data distribution server with the threshold value, and the radio field intensity between the data receiving terminal and the data distribution server is equal to or greater than the threshold value. It is preferable that the defect portion is determined to be repaired.

According to the present invention, the radio wave intensity between the data receiving terminal 20 and the data distribution server 10 is taken into consideration as a condition, so that, for example, the download is automatically performed when returning to the area from outside the area such as underground. Can be executed.

Further, in the data receiving terminal of the present invention, the data related status includes a past received data usage rate calculated based on a usage history of past received data that is data received in the past from the data distribution server, and the communication status. And the repair determination means compares the past received data usage rate with the usage rate threshold Z, and the past received data usage rate is When the threshold value Z is equal to or greater than the threshold value Z, it is preferable that the user of the data receiving terminal determines that the missing portion is to be repaired before using the data.

Further, in the data distribution method of the present invention, the data-related status includes a past received data usage rate calculated based on a usage history of past received data that is data received in the past from the data distribution server, and the communication status. And the repair determination means compares the past received data usage rate with the usage rate threshold Z, and the past received data usage rate is When the threshold value Z is equal to or greater than the threshold value Z, it is preferable that the user of the data receiving terminal determines that the missing portion is to be repaired before using the data.

This invention provides a countermeasure for the third problem “selection of target data for file restoration”. According to the present invention, by using the past received data utilization rate as a parameter representing the probability that the distribution data is actually used, the condition judgment is performed on the data that may be subjected to the file restoration procedure and the data that should not be performed. Thus, it is possible to execute the file repair procedure only for data having a predetermined utilization rate threshold value Z or higher.

Further, in the data receiving terminal of the present invention, the communication status is a relationship between a current time and a preset time zone, and the threshold value Z of the utilization rate is
Z = C1 / C2 (1)
(However, C1 is a communication cost when communication is performed by the communication wave transmission / reception function within the preset time zone, and C2 is communication by the communication wave transmission / reception function outside the preset time zone. It is the communication cost when going.)
It is preferable that

In the data distribution method of the present invention, the communication status is a relationship between a current time and a preset time zone, and the threshold Z of the utilization rate is
Z = C1 / C2 (1)
(However, C1 is a communication cost when communication is performed by the communication wave transmission / reception function within the preset time zone, and C2 is communication by the communication wave transmission / reception function outside the preset time zone. It is the communication cost when going.)
It is preferable that

As a countermeasure for the third problem, “Selection of target data for file restoration”, the communication status is the relationship between the current time and a preset time zone. It is preferable to calculate the utilization rate threshold Z based on the mathematical formula (1).

Further, in the data receiving terminal of the present invention, the threshold value Z of the utilization rate is
Z = (C1 / C2) × W (2)
(W is a weight according to the genre of data transmitted from the data distribution server.)
It is preferable that

In the data distribution method of the present invention, the threshold value Z of the utilization rate is
Z = (C1 / C2) × W (2)
(W is a weight according to the genre of data transmitted from the data distribution server.)
It is preferable that

As a countermeasure against the third problem “selection of target data for file restoration”, it is preferable to calculate the utilization threshold Z based on the above formula (2). In this case, since the utilization threshold value Z can be calculated in accordance with the characteristics of the distribution data, calculation with higher accuracy is possible.

Further, in the data receiving terminal of the present invention, the communication status includes a network usage contract type currently concluded between the data receiving terminal and the data distribution server, and a preset network usage contract type. And the utilization threshold Z is
Z = C3 / C4 (3)
(However, C3 is a communication cost when communication is performed by the communication wave transmission / reception function based on the preset network use contract, and C4 is a use contract other than the preset network use contract. This is the communication cost when communication is originally performed by the communication wave transmission / reception function.)
It is preferable that

Further, in the data distribution method of the present invention, the communication status includes a network usage contract type currently concluded between the data receiving terminal and the data distribution server, and a preset network usage contract type. And the utilization threshold Z is
Z = C3 / C4 (3)
(However, C3 is a communication cost when communication is performed by the communication wave transmission / reception function based on the preset network use contract, and C4 is a use contract other than the preset network use contract. This is the communication cost when communication is originally performed by the communication wave transmission / reception function.)
It is preferable that

The countermeasure for the third issue, “Selection of target data for file restoration”, is the type of network usage contract currently concluded between the data receiving terminal and the data distribution server. And the threshold value Z of the utilization rate is preferably calculated based on the above formula (3).

Further, in the data receiving terminal of the present invention, the broadcast wave receiving means uses the broadcast wave receiving function to transmit the pre-acquired data, which is a predetermined part of data received from the data distribution server, to the data distribution terminal. Received from a server, the data related status is whether or not there is an unreceived portion in the pre-acquired data, and the repair determining means determines that the unacquired portion is in the pre-acquired data In addition, it is preferable that the user of the data receiving terminal determines to repair the unreceived part before using the data.

Further, in the data distribution method of the present invention, the broadcast wave receiving means uses the broadcast wave reception function to transmit the pre-acquired data, which is a predetermined part of the data received from the data distribution server, to the data distribution. Received from a server, the data related status is whether or not there is an unreceived portion in the pre-acquired data, and the repair determining means determines that the unacquired portion is in the pre-acquired data In addition, it is preferable that the user of the data receiving terminal determines to repair the unreceived part before using the data.

This invention provides another countermeasure against the third problem “selection of target data for file restoration”. According to the present invention, the data receiving terminal can distinguish between data that should be subjected to the file restoration procedure in advance (pre-acquired data) and data that is not so, and can download only the pre-acquired data in advance. .

In the data receiving terminal of the present invention, it is preferable that the pre-acquired data is a head portion of data received from the data distribution server.

In the data distribution method of the present invention, it is preferable that the pre-acquired data is a head portion of data received from the data distribution server.

Since the top part of the distribution data (data at the start of use) has a high probability of being referred to by the user in order to confirm the content of the distribution data, the data to be executed in advance. Appropriate as.

In the data receiving terminal of the present invention, the size of the pre-acquired data is
x = D-TV (4)
(Where x is the size of the previously acquired data, D is the total size of the data received from the data distribution server, T is the reproduction time of the data, and V is the network in the communication wave transmission / reception function) The average bit rate of
It is preferable that

In the data distribution method of the present invention, the size of the pre-acquired data is
x = D-TV (4)
(Where x is the size of the previously acquired data, D is the total size of the data received from the data distribution server, T is the reproduction time of the data, and V is the network in the communication wave transmission / reception function) The average bit rate of
It is preferable that

As another measure for the third problem “selection of target data for file restoration”, it is preferable to calculate the size of the pre-acquired data based on the above formula (4). As a result, it is possible to compensate for all missing parts before the reproduction of the distribution data is completed.

In the data receiving terminal of the present invention, the size of the pre-acquired data is a past received data portion calculated based on a usage history in each portion of past received data that is data received in the past from the data distribution server. It is preferable that the total size of each part, which is calculated based on a utilization rate and whose past reception data partial utilization rate is equal to or greater than a predetermined threshold, is calculated as the size of the pre-acquired data.

In the data distribution method of the present invention, the size of the pre-acquired data is a past received data portion calculated based on a usage history in each portion of past received data that is data received in the past from the data distribution server. It is preferable that the total size of each part, which is calculated based on a utilization rate and whose past reception data partial utilization rate is equal to or greater than a predetermined threshold, is calculated as the size of the pre-acquired data.

In another measure for the third problem, “Selecting target data for file restoration”, the total size of each part whose past received data part usage rate is equal to or greater than a predetermined threshold is used as the size of the pre-acquired data. It is preferable to calculate. As a result, it is possible to previously download a portion having a high data use probability as pre-acquired data.

Also, in the data receiving terminal of the present invention, the broadcast wave receiving means uses the broadcast wave receiving function to transmit the metadata in which at least one of the communication status and the data related status is described. It is preferable to receive from the server.

Further, in the data distribution method of the present invention, the broadcast wave receiving means uses the broadcast wave reception function to transmit the metadata in which at least one of the communication status and the data related status is described. It is preferable to receive from the server.

The metadata may be created and managed on the data distribution server side and transmitted to the data receiving terminal.

In the data receiving terminal of the present invention, it is preferable that the storage unit stores metadata describing at least one of the communication status and the data related status.

In the data distribution method of the present invention, it is preferable that the storage unit stores metadata in which at least one of the communication status and the data related status is described.

The metadata may be created and managed by the data receiving terminal itself and used.

In the data distribution server of the present invention, in response to the retransmission request, at least one of a communication status between the data distribution server and the data receiving terminal and a data related status that is a status related to the data And a retransmission determination means for determining whether or not to retransmit the missing portion, and when the retransmission determining means determines that the missing portion is to be retransmitted, the missing portion transmitting means determines the missing portion as the data. It is preferable to transmit to the receiving terminal using the communication wave transmission / reception function.

According to this invention, the data distribution server is related to the communication status between the data receiving terminal and the data distribution server and the distribution data in response to the retransmission request from the data receiving terminal to retransmit the missing portion of the distribution data. Based on at least one of the data-related situations, which is a situation to be performed, it is determined whether or not to repair the missing portion. Since it is properly determined whether or not to perform the defect repair process based on the communication status and the data-related status, wasteful communication costs can be reduced when repairing the missing portion in data communication using broadcast waves with a communication wave. It becomes possible not to generate.

Further, in the data distribution server of the present invention, the data-relevant status is a past received data usage rate calculated based on a usage history of past received data that is data received by the data receiving terminal in the past from the data distribution server. And the utilization rate threshold Z calculated based on the communication status, the retransmission determination means compares the past received data utilization rate with the utilization rate threshold Z, and the past When the reception data usage rate is equal to or higher than the threshold value Z, it is preferable that the user of the data receiving terminal determines to retransmit the missing portion to the data receiving terminal before using the data.

In the data distribution server of the present invention, the communication status is a relationship between a current time and a preset time zone, and the threshold Z of the utilization rate is
Z = C1 / C2 (1)
(However, C1 is a communication cost when communication is performed by the communication wave transmission / reception function within the preset time zone, and C2 is communication by the communication wave transmission / reception function outside the preset time zone. It is the communication cost when going.)
It is preferable that

Further, in the data distribution server of the present invention, the communication status includes a network usage contract type currently concluded between the data receiving terminal and the data distribution server, and a preset network usage contract type. And the utilization threshold Z is
Z = C3 / C4 (3)
(However, C3 is a communication cost when communication is performed by the communication wave transmission / reception function based on the preset network use contract, and C4 is a use contract other than the preset network use contract. This is the communication cost when communication is originally performed by the communication wave transmission / reception function.)
It is preferable that

Further, in the data distribution server of the present invention, the data transmission means uses the broadcast wave reception function to transmit the metadata describing at least one of the communication status and the data related status to the data receiving terminal. It is preferable to transmit to.

According to the present invention, a data receiving terminal, a data distribution server, a data distribution system, and a data distribution method capable of not generating unnecessary communication costs when repairing a missing portion in data communication using a broadcast wave with a communication wave Can be provided.

1 is a schematic configuration diagram of a data distribution system 1. FIG. 2 is a hardware configuration diagram of a data distribution server 10 and a data receiving terminal 20. FIG. 2 is a configuration block diagram showing a functional configuration of a data distribution server 10. FIG. 3 is a configuration block diagram showing a functional configuration of a data receiving terminal 20. FIG. It is a sequence diagram for demonstrating the procedure when general data download is performed based on the structure of the data delivery system. It is a flowchart which shows the processing flow in a time shift download system. It is a figure which shows the example of the variable name recorded on the metadata used by this embodiment, and its value. It is a flowchart which shows the processing flow in a network adaptive download system. It is a figure which illustrates the mode of the distribution data preserve | saved at the data storage part 240, after acquiring delivery data. It is a flowchart which shows the processing flow in a partial data download system. It is a sequence diagram for demonstrating the procedure of a partial data download system based on the whole structure of the data delivery system. It is a figure which shows the example from which a utilization probability differs for every part of delivery data. It is a figure which shows the example from which a utilization probability differs for every part of delivery data.

DESCRIPTION OF SYMBOLS 1 ... Data delivery system, 10 ... Data delivery server, 110 ... Storage part, 120 ... Data transmission part, 130 ... Retransmission request reception part, 140 ... Retransmission judgment part, 150 ... Missing part transmission part, 20 ... Data reception terminal,

Communication Control unit

210, 220 ... determination unit, 230 input / output control unit, 240 data storage unit, 30 communication network.

Hereinafter, preferred embodiments of a data receiving terminal, a data distribution server, a data distribution system, and a data distribution method according to the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(Overall configuration of data distribution system 1)
First, the configuration of the data distribution system 1 according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic configuration diagram of a data distribution system 1. As shown in FIG. 1, the data distribution system 1 includes a data distribution server 10 and a data receiving terminal 20, and the data distribution server 10 and the data receiving terminal 20 are connected to each other by a communication network 30.

The data distribution server 10 holds various types of data that can be used by the user who owns the data receiving terminal 20, and uses the broadcast wave transmission function and the communication wave transmission / reception function to distribute data to the data receiving terminal 20 (patents). This corresponds to “data” in the claims.), And has a function of distributing metadata and the like.

The data receiving terminal 20 is a terminal that receives distribution data, metadata, and the like distributed by the data distribution server 10 using a broadcast wave reception function and a communication wave transmission / reception function. The data receiving terminal 20 is a mobile phone, for example. The user can use various services by using the distribution data downloaded to the data receiving terminal 20. FIG. 1 shows

data receiving terminals

20A, 20B, and 20C as the data receiving terminal 20, and the data receiving terminal 20 is a generic name for the

data receiving terminals

20A, 20B, and 20C.

The network 30 is a broadcasting network or a communication network for distributing various data including distribution data, such as a mobile communication network, wireless LAN, WiMAX, and multimedia broadcasting. For example, when the network 30 is a multimedia broadcast, distribution data is transmitted and received between the network 30 and the data receiving terminal 20 using the broadcast network. When the network 30 is configured by UMTS, transmission / reception of distribution data is executed between the network 30 and the data receiving terminal 20 using a mobile communication network.

(Configuration of data distribution server 10)
Hereinafter, the data distribution server 10 will be described in more detail. FIG. 2 is a hardware configuration diagram of the data distribution server 10. As shown in FIG. 2, the data distribution server 10 physically includes a CPU 11, a main storage device such as a ROM 12 and a RAM 13, an input device 14 such as a keyboard and a mouse, an output device 15 such as a display, and a data receiving terminal 20. Are configured as a normal computer system including a communication module 16 such as a network card for transmitting and receiving data, an auxiliary storage device 17 such as a hard disk, and the like. Each function of the data distribution server 10 to be described later causes the input device 14, the output device 15, and the communication module 16 to be controlled under the control of the CPU 11 by reading predetermined computer software on hardware such as the CPU 11, the ROM 12, and the RAM 13. This is realized by operating and reading and writing data in the

main storage devices

12 and 13 and the auxiliary storage device 17.

FIG. 3 is a configuration block diagram showing a functional configuration of the data distribution server 10. As shown in FIG. 3, the data distribution server 10 functionally includes a storage unit 110, a data transmission unit 120 (data transmission unit), a retransmission request reception unit 130 (retransmission request reception unit), and a retransmission determination unit 140 (retransmission). A determination unit) and a defective portion transmission unit 150 (defect portion transmission unit).

The storage unit 110 stores distribution data for distribution to the data receiving terminal 20. The storage unit 110 also includes metadata describing at least one of a communication status between the data distribution server 10 and the data receiving terminal 20 and a data related status that is various statuses related to the distribution data. Hold. In this metadata, at least one of the communication status and the data related status is described, and for example, the size, type, content, delivery time, location, etc. of the delivery data are recorded. For details on metadata, see http://www.arib.or.jp/tyosakenkyu/kikaku_hoso/hoso_std-b038.html (searched on September 25, 2008) and http://www.3gpp.org/ See further ftp / Specs / html-info / 26346.htm (searched 25 September 2008). Details of the communication status and the data related status will be described later.

The data transmission unit 120 transmits distribution data to the data receiving terminal 20 using a broadcast wave transmission function. In addition, the data transmission unit 120 transmits the metadata to the data reception terminal 20 using the broadcast wave reception function. The data transmission unit 120 acquires distribution data and metadata from the storage unit 110 and transmits them.

The retransmission request receiving unit 130 is requested by the data receiving terminal 20 to retransmit the missing portion of the distribution data using the communication wave transmission / reception function.

The retransmission determination unit 140 responds to a retransmission request from the data receiving terminal 20 and includes at least one of a communication status between the data distribution server 10 and the data receiving terminal 20 and a data related status that is a status related to distribution data. Based on one, it is determined whether or not to retransmit the missing portion of the distribution data. Retransmission determination section 140 outputs the determination result to missing part transmission section 150.

When the retransmission determining unit 140 determines to retransmit the missing part of the distribution data, the missing part transmitting unit 150 transmits the missing part to the data receiving terminal 20 using the communication wave transmission / reception function. The missing part transmission unit 150 acquires the missing part of the distribution data from the storage unit 110 and transmits it.

(Configuration of data receiving terminal 20)
Hereinafter, the data receiving terminal 20 will be described in more detail. FIG. 2 is a hardware configuration diagram of the data receiving terminal 20. As shown in FIG. 2, the data receiving terminal 20 physically includes a CPU 21, a ROM 22 and a RAM 23 that are main storage devices, an input device 24 such as an operation button, an output device 25 such as an LCD or an organic EL display, and data distribution. A communication module 26 that transmits and receives data to and from the server 10 and an auxiliary storage device 27 such as a memory device are provided. Each function of the data receiving terminal 20, which will be described later, operates the input device 24, the output device 25, and the communication module 26 under the control of the CPU 21 by loading predetermined software on the hardware such as the CPU 21, the ROM 22, and the RAM 23. In addition, it is realized by reading and writing data in the

main storage devices

22 and 23 and the auxiliary storage device 27.

FIG. 4 is a configuration block diagram showing a functional configuration of the data receiving terminal 20. As shown in FIG. 4, the data receiving terminal 20 functionally includes a communication control unit 210 (broadcast wave receiving means and communication wave transmission / reception means), a determination unit 220 (repair determination means), an input / output control unit 230, and A data storage unit 240 (storage means) is provided.

The communication control unit 210 is a part that controls communication of the data receiving terminal 20, and performs data transmission / reception with the data distribution server 10 via the network 30. The communication control unit 210 can use both multimedia broadcasting and a mobile communication network. That is, the communication control unit 210 can receive distribution data and metadata from the data distribution server 10 using the broadcast wave reception function. In addition, when the determination unit 220, which will be described later, determines that the missing portion of the distribution data is repaired, the communication control unit 210 requests the data distribution server 10 to retransmit the missing portion using the communication wave transmission / reception function. And the said defect | deletion part transmitted from the data delivery server 10 based on the said resending request | requirement can be received using a communication wave transmission / reception function.

The determination unit 220 determines whether or not there is a missing portion in the distribution data from the data distribution server 10, and when it is determined that there is a missing portion, the communication status between the data receiving terminal 20 and the data distribution server 10 And determining whether or not to repair the missing portion based on at least one of the data-related situations, which are situations relating to the distribution data. The detailed operation of the determination unit 220 will be described later.

The input / output control unit 230 is an input / output part that receives a screen display to the user and an instruction from the user, and corresponds to, for example, the input device 24 and the output device 25 in FIG. The input / output control unit 230 acquires the distribution data and the missing portion from the data storage unit 240 and displays it on the screen.

The data storage unit 240 is a part that accumulates distribution data downloaded from the data distribution server 10 and missing portions of the distribution data. The data storage unit 240 stores data stored in the data storage unit 240 to the user using the input / output control unit 230. By displaying, the user can use the distribution data from the data distribution server 10 and the missing portion thereof. The data storage unit 240 can store metadata and other related information in addition to the distribution data. This metadata may be created and managed on the data distribution server 10 side and transmitted to the data receiving terminal 20, or may be created, managed and used by the data receiving terminal 20 itself. Good. The data storage unit 240 can be configured by the RAM 23 and the auxiliary storage device 27 in FIG. 3, for example.

(Operation of data distribution system 1)
Next, operations performed by the data distribution system 1 will be described.

(General data download procedure)
Before describing the operation of the data distribution system 1 according to the present invention, a general data download procedure will be described with reference to FIG. FIG. 5 is a sequence diagram for explaining a procedure when a general data download is performed based on the configuration of the data distribution system 1 shown in FIGS.

First, before receiving the distribution data, the data receiving terminal 20 acquires metadata for the distribution data to be downloaded as necessary (step 101a). FIG. 5 shows a state in which metadata is distributed by broadcast distribution of multimedia broadcasting, and a state in which the

data receiving terminals

20A, 20B, and 20C are simultaneously receiving metadata. In this example using FIG. 5, it is assumed that distribution time information indicating the timing at which distribution data is broadcast-distributed is recorded in the metadata. In addition to the method of using the exemplified broadcast, there is a method of acquiring metadata individually from the data distribution server 10 by unicast. Further, this step may be skipped when there is no metadata.

Next, based on the distribution time information included in the metadata, the data receiving terminal 20 receives distribution data distributed by multimedia broadcasting at the timing (step 102a). The example of FIG. 5 shows an example in which data distribution is performed three times in order to complete the data distribution. All three data distributions are completed and all the data D1, D2, and D3 are distributed. An example of completion as data usable by the user is shown.

Further, the example of FIG. 5 shows an example in which the data receiving terminal 20B fails to receive the third data and the data D3 cannot be downloaded. As reasons for the failure of data reception in this way, for example, the power reception of the data reception terminal 20B or the radio wave reception quality of the data reception terminal 20B has been considered.

The data receiving terminal 20B that has failed to receive data then performs complementation of the missing portion, that is, the data D3 by the file repair procedure (step 103a). In the example of FIG. 5, the data D3 that has failed to be received is requested to be complemented by unicast using, for example, HTTP (HypertextperTransfer Protocol) on the mobile communication network, and the data D3 that is retransmitted in response to the request is received. It shows that. By performing data complement by unicast in this way, the data receiving terminal 20 can reliably complement the missing data D3. Such a file repair procedure has various forms such as a method automatically executed by the data receiving terminal 20 and a method executed after waiting for an instruction from the user.

According to the procedure described above, downloading of all distribution data is completed, and the user who owns the data receiving terminal 20 can use the distribution data. However, in the above method, the three problems as described above, that is, the first problem “delivery time zone”, the second problem “type of network to be used”, and the third problem The issue of “selection of target data for file restoration”, which is the issue, is not considered at all, and the above three issues still remain. Therefore, in the following, a method for solving each of the above problems will be described.

(Time shift download method)
First, a countermeasure for the first problem “delivery time zone” will be described. This countermeasure for the first problem is hereinafter referred to as “time shift download method”.

In the data download method shown in FIG. 5, since the file restoration procedure is performed by unicast communication, communication traffic may be compressed depending on the time zone. For example, when the file restoration procedure shown in FIG. 5 is executed in a time zone where the traffic volume is large (for example, from evening to night), the problem of traffic compression becomes particularly large. Therefore, the time-shift download method provides a mechanism for executing a file restoration procedure only during a time zone when the network traffic is low.

FIG. 6 is a flowchart showing a processing flow in the time shift download method. FIG. 7 shows examples of variable names and their values recorded in the metadata used in this embodiment.

First, the communication control unit 210 of the data receiving terminal 20 acquires metadata (step 201a) and distribution data using multimedia broadcasting (step 202a). The processing of step 201a and step 202a is equivalent to the processing of step 101a and step 102a shown in FIG.

After that, when the determination unit 220 of the data receiving terminal 20 determines that a missing portion exists (step 203a), next, the missing portion is repaired based on the communication status between the data receiving terminal 20 and the data distribution server 10. Whether or not (step 204a). The “communication status” at this time is a relationship between the current time and a preset time zone. Specifically, the determination unit 220 compares the time zone indicated by the DLDulation described in the metadata shown in FIG. 7 with the current time. The DLDulation describes a time period during which file restoration may be performed, and the data distribution server 10 distributes the meta information including this information to the data receiving terminal 20. Here, when the determination unit 220 determines that the current time is within the time zone represented by the DLDulation, that is, determines that it is a time when the file repair may be performed (step 204a: Yes), the determination unit 220 repairs the missing portion. Judgment is made and a file repair procedure is executed (step 205a).

If the determination unit 220 determines that the current time is a time when the file repair should not be performed (step 204a: No), the determination unit 220 ends without executing the file repair procedure (step 206a: No), or the file repair procedure. (Step 206a: Yes). When waiting for a time when the file repair procedure may be executed, the process returns to step 204a. Note that whether to wait until a time when the file repair procedure may be executed is described in the metadata. Specifically, it corresponds to TimeWaitOK shown in FIG. 7, and when it is OK, it waits until the file repair procedure can be executed.

By the above procedure, the data receiving terminal 20 can perform the condition determination for the time zone when the file restoration procedure may be executed and the time zone when the file restoration procedure should not be executed, and in the time zone where the network traffic is concentrated. It is possible to prevent the execution of the file repair procedure.

In the above description, DLDulation and TimeWaitOK are described in the metadata, and the procedure in which the data distribution server 10 notifies the data receiving terminal 20 has been described. 20 may be stored. In this case, whether or not to execute the file restoration procedure is determined based on DLDulation and TimeWaitOK described in the metadata stored in advance in the data storage unit 240 of the data receiving terminal 20.

(Network adaptive download method)
Next, a countermeasure for the second problem “type of network to be used” will be described. This countermeasure for the second problem is hereinafter referred to as “network adaptive download method”.

In the data download method shown in FIG. 5, since the file restoration procedure is performed by unicast communication, the communication cost may increase depending on the network used. Therefore, the network adaptive download method provides a mechanism for selecting a network with a low communication cost and executing a file repair procedure. The “communication cost” refers to a value related to the network, such as a communication fee, network capacity, transmission speed, and delay time. For example, when considering a communication fee as a communication cost, a data communication fee increases when a mobile communication network is used, but a communication fee may be reduced when a wireless LAN is used instead. From the above, when the data receiving terminal 20 can select a plurality of communication methods, it may be better to execute the file restoration procedure using the communication method with the lowest communication cost.

FIG. 8 is a flowchart showing a processing flow in the network adaptive download method. FIG. 7 shows examples of variable names and their values recorded in the metadata used in this embodiment.

First, the communication control unit 210 of the data receiving terminal 20 acquires metadata (step 301a) and distribution data using multimedia broadcasting (step 302a). The processing of step 301a and step 302a is equivalent to the processing of step 101a and step 102a shown in FIG.

Thereafter, when the determination unit 220 of the data receiving terminal 20 determines that a missing portion exists (step 303a), next, the missing portion is repaired based on the communication status between the data receiving terminal 20 and the data distribution server 10. Whether or not (step 304a). The “communication status” at this time is a relationship between a network type currently available between the data receiving terminal 20 and the data distribution server 10 and a preset network type. The “communication status” is the relationship between the type of base station currently available in the currently available network and the type of base station preset in relation to the currently available network. May be. Hereinafter, a case where the communication status includes both the network type and the base station type will be described as an example.

Specifically, the determination unit 220 compares the network type represented by DLNetwork described in the metadata shown in FIG. 7 with the network type currently available. Further, the determination unit 220 compares the type of the base station represented by the DLNetwork described in the metadata shown in FIG. 7 with the type of the currently available base station. Note that DLNetwork describes the type of network and the type of base station that may execute file restoration, and the data distribution server 10 includes this information in the meta information to the data receiving terminal 20. To deliver. The network type and the base station type may be arranged in descending order from the highest priority. The priority is determined by, for example, the communication cost.

Here, the determination unit 220 determines whether there is a match between the currently available network type and the network type represented by the DLNetwork, and the currently available base station type and the base station represented by the DLNetwork. If there is a match in both types, that is, if it is determined that the network and base station that may perform file repair are currently available (step 304a: Yes), it is determined to repair the missing part. Then, a file repair procedure is executed (step 305a).

If the determination unit 220 determines that there is no available network or base station that may perform file repair (step 304a: No), the file repair procedure is not executed and the process ends. (Step 306a: No) or wait until a network and base station that can perform the file repair procedure become available (step 306a: Yes). If waiting until a network and base station that can perform the file repair procedure are available, the process returns to step 304a. Note that whether to wait until a time when the file repair procedure may be executed is described in the metadata. Specifically, it corresponds to NWWaitOK shown in FIG. 7, and when it is OK, it waits until a file repair procedure can be executed.

By the above procedure, the data receiving terminal 20 can perform a condition determination for the network and base station that may execute the file repair procedure, and the network and base station that should not be executed, and the communication cost is lower. It is possible to execute a file repair procedure using.

In the above description, DLNetwork and NwWaitOK are described in the metadata, and the procedure in which the data distribution server 10 notifies the data receiving terminal 20 has been described. 20 may be stored. In this case, whether to execute the file repair procedure is determined based on DLNetwork and NwWaitOK described in the metadata stored in advance in the data storage unit 240 of the data receiving terminal 20.

(Other examples of communication status)
In the time-shift download method described above, the relationship between the current time and a preset time zone is set as a communication status, and whether or not the determination unit 220 of the data receiving terminal 20 repairs the missing portion based on this communication status. Judged. Further, in the network adaptive download method described above, the relationship between the network type currently available between the data receiving terminal 20 and the data distribution server 10 and the preset network type, and the above-described current use is possible. The relationship between the type of base station currently available in a simple network and the type of base station preset in relation to the currently available network is a communication status, and the determination unit 220 of the data receiving terminal 20 Based on this communication situation, it was determined whether or not to repair the missing part. Hereinafter, another example of the communication status will be described.

(Other examples of communication status, part 1)
The communication status may be a relationship between the remaining battery level of the data receiving terminal 20 and a preset remaining battery level threshold. In this case, the determination unit 220 of the data receiving terminal 20 compares the remaining battery level of the data receiving terminal 20 with the above threshold value, and if the remaining battery level of the data receiving terminal 20 is equal to or greater than the above threshold value, Judge to repair.

Thus, by considering the remaining battery level of the data receiving terminal 20 as a condition, for example, when the remaining battery level is low, it is possible to prevent the battery from running out by performing the download. In addition, not only when the battery remaining amount of the data receiving terminal 20 is more than the above threshold value, but also when it is being charged, it may be determined to repair the missing part.

(Other examples of communication status, part 2)
The communication status may be a relationship between the type of the network usage contract currently concluded between the data receiving terminal 20 and the data distribution server 10 and the preset type of the network usage contract. In this case, the determination unit 220 of the data receiving terminal 20 compares the currently used network usage contract type with a preset network usage contract type, and there is a match between the two types. In addition, it is determined to repair the missing part.

Thus, by considering the type of network usage contract between the data receiving terminal 20 and the data distribution server 10 as a condition, it is possible to prevent an unexpectedly high communication fee from being generated. For example, there may be users who are subscribed to the flat-rate plan and users who are not so even with the same mobile communication network, and when data download is automatically performed for users who are not subscribed to the flat-rate plan, Unexpected charges may occur. In order to prevent this, for example, it is conceivable to automatically download data only to users who subscribe to a flat-rate plan.

(Other examples of communication status, part 3)
The communication status may be a relationship between the radio wave intensity between the data receiving terminal 20 and the data distribution server 10 and a preset threshold of the radio wave intensity. In this case, the determination unit 220 of the data receiving terminal 20 compares the radio wave intensity between the data receiving terminal 20 and the data distribution server 10 with the above threshold value, and between the data receiving terminal 20 and the data distribution server 10. When the radio wave intensity is equal to or higher than the threshold value, it is determined that the missing portion is repaired.

In this way, by considering the radio wave intensity between the data receiving terminal 20 and the data distribution server 10 as a condition, for example, the download is automatically executed when returning to the area from outside the area such as underground. be able to. Specifically, for example, an example in which a missing portion of distribution data is automatically downloaded when returning to a service area when getting off the subway can be considered.

In the above description regarding other examples of the communication status, each threshold value may be described in the metadata, and the data distribution server 10 may notify the data receiving terminal 20. Alternatively, the data receiving terminal 20 may store metadata including a description about each threshold value in advance. In this case, whether to execute the file restoration procedure is determined based on each threshold value described in the metadata stored in advance in the data storage unit 240 of the data receiving terminal 20.

(Data usage adaptation download method)
Next, a countermeasure for the third problem “selection of target data for file restoration” will be described. This countermeasure for the third problem is hereinafter referred to as “data usage adaptive download method”. The data usage status adaptive download method is a mechanism that considers the data usage status when determining whether or not to execute a file restoration procedure.

The determination unit 220 of the data receiving terminal 20 determines whether or not to repair the missing part based on the data related situation that is the situation related to the distribution data. Here, the “data related status” represents the usage status of the distribution data, and is based on the past received data usage rate p calculated based on the usage history of the past received data and the communication status described above. This is the relationship between the calculated utilization rate threshold Z. The past received data is distribution data that the data receiving terminal 20 has received from the data distribution server 10 in the past. Specifically, the determination unit 220 of the data receiving terminal 20 compares the past received data usage rate p with the threshold Z of the usage rate, and when the past received data usage rate p is equal to or greater than the threshold Z, the above-described time Based on the shift download method or the network adaptive download method, it is determined that the user of the data receiving terminal 20 will repair the missing portion in advance before using the distribution data.

As described above, it is possible to make a condition judgment on data that can be executed by the file restoration procedure and data that should not be executed by using the past received data usage rate p as a parameter representing the probability that the delivery data is actually used. Thus, the file restoration procedure can be executed only for data having a predetermined usage rate threshold value Z or higher.

Here, the threshold Z of the utilization rate can be calculated based on the following formula (1).
Z = C1 / C2 (1)
However, in the above equation (1), when the communication status is a relationship between the current time and a preset time zone, that is, when DLDulation is used as a determination criterion under the time shift download method, C1 is a communication cost when communication is performed by the communication wave transmission / reception function within a preset time zone (for example, a night time zone where the traffic volume is low), and C2 is outside the preset time zone (eg, the traffic volume). It is the communication cost when communication is performed by the communication wave transmission / reception function during daytime hours when there are many.

The background from which the above formula (1) was derived is as follows. For example, the total communication cost A in the case where all missing portions are repaired in advance within a preset time zone is:
A = D × C1 (5)
Can be expressed as However, D is the data size of a missing part. On the other hand, the total communication cost B in the case where the user request occurs outside the preset time zone and the missing portion is repaired after the occurrence is as follows:
B = D × C2 × p (6)
Can be expressed as In the case of the communication cost B, since the missing portion is repaired only when the data is actually used, the past received data usage rate p is included as a parameter representing the probability that the data is actually used.

Here, when the formula (5) is compared with the formula (6), when the cost A of the formula (5) is smaller, the user has repaired the missing portion in advance before using the distribution data. It is considered that the total cost can be kept low. For this reason,
D × C1 ≦ D × C2 × p (7)
It can be said that there is an effect of pre-downloading the missing portion when p is such that In addition, when calculating Formula (7),
p ≧ C1 / C2 (8)
Therefore, it can be said that it is better to download the missing portion in advance when p satisfies this value.

From the above, the threshold Z of the utilization rate is set to Z = C1 / C2 (1)
We decided to calculate based on. Further, the determination unit 220 of the data receiving terminal 20 compares the past received data usage rate p with the threshold Z of the usage rate, and when the past received data usage rate p is equal to or greater than the threshold Z, that is, Equation (8) In the case of the past received data utilization rate p that satisfies, based on the time-shift download method described above, it is determined that the user of the data receiving terminal 20 will repair the missing part in advance before using the distribution data.

To explain using specific values, when the communication cost C1 is 1/10 of the communication cost C2, if the past received data usage rate p is more than 10%, it is advantageous to download the missing portion in advance. If it is less than 10%, it can be said that the prior download of the missing part is disadvantageous.

Moreover, the threshold Z of the utilization rate can be calculated based on the following formula (3).
Z = C3 / C4 (3)
However, in the above formula (3), the communication status is between the type of the network usage contract currently concluded between the data receiving terminal 20 and the data distribution server 10 and the preset type of the network usage contract. In other words, that is, when DLNetwork is used as a criterion for determination based on the network adaptive download method, C3 is used when communication is performed using a communication wave transmission / reception function based on a preset network usage contract. C4 is a communication cost (for example, a communication cost for a WLAN with a low communication fee), and C4 is a communication cost (for example, communication) when communication is performed by the communication wave transmission / reception function based on a usage contract other than a preset network usage contract. The communication cost of a mobile communication network with a relatively high charge).

The background from which the above formula (3) is derived is the same as the background from which the above formula (1) is derived, and the description thereof will be omitted. However, from the derivation background of the above formula (1), “C1” is read as “C3”, “C2” is read as “C4”, and “time shift download method” is read as “network adaptive download method”, It is possible to easily understand the derivation background of Equation (3).

In the data usage situation adaptive download method described above, the communication costs C1, C2, C3, C4 and the past received data usage rate p need to be calculated in advance. Therefore, the data receiving terminal 20 may notify the data distribution server 10 of the usage status (usage history) of the data of its own terminal. For the notification of data usage history, a method of notifying the data distribution server 10 by HTTP or the like is conceivable as in the MBMS reception reporting procedure (Reception Reporting Procedure). The data distribution server 10 that has received the data usage history calculates the past received data usage rate p based on the usage history. Further, the data distribution server 10 calculates a condition for satisfying Expression (8) from the communication costs C1, C2, C3, and C4 calculated in advance. And the data delivery server 10 can determine DLDulation and DLNetwork based on the conditions in which Numerical formula (8) is materialized. Note that the data receiving terminal 20 calculates the past received data usage rate p at its own terminal without notifying the data distribution server 10 of the usage history, calculates the condition for satisfying the formula (8), and further calculates the DLDulation or DLNetwork may be calculated.

About the above calculation, it can also divide by the genre of delivery data instead of calculating | requiring uniformly about all the delivery data. For example, when the usage probability of soccer content is high as a taste preference of a certain user, another past received data usage rate p may be calculated for the soccer content. That is,
Z = (C1 / C2) × W (2)
To calculate the utilization threshold Z.
p ≧ C1 / C2 × W (9)
The past received data utilization rate p satisfying the above may be calculated. However, in Equations (2) and (9), W is a weight corresponding to the genre of soccer content in the distribution data transmitted from the data distribution server 10.

As described above, the threshold Z of the utilization rate can be calculated according to the characteristics of the distribution data, so that calculation with higher accuracy is possible.

(Partial data download method)
Next, another countermeasure for the third problem “selection of target data for file restoration” will be described. This countermeasure for the third problem is hereinafter referred to as “partial data download method”. The partial data download method is a mechanism for actively selecting data to be repaired and executing a file repair procedure. Hereinafter, a predetermined part of distribution data, which should be acquired in advance before the user uses the distribution data, is referred to as “pre-acquisition data”.

The communication control unit 210 of the data receiving terminal 20 receives distribution data including pre-acquired data from the data distribution server 10 using the broadcast wave receiving function. Next, the determination unit 220 of the data receiving terminal 20 is based on a data-related situation that is a situation relating to the distribution data, particularly a missing part (particularly a missing part in the pre-acquired data, hereinafter referred to as “unreceived part”). ) To determine whether to repair. Here, the “data related situation” is whether or not there is an unreceived part in the pre-acquired data. That is, when there is an unreceived portion in the pre-acquired data, the determination unit 220 of the data receiving terminal 20 determines that the unreceived portion is repaired before the user of the data receiving terminal 20 uses the distribution data.

FIG. 9 is a diagram illustrating the state of the distribution data stored in the data storage unit 240 after acquiring the distribution data (for example, after step 102a in FIG. 5). It is a figure for demonstrating the missing part in unreceived parts, delivery data other than prior acquisition data, and delivery data other than prior acquisition data. In FIG. 9, the downloaded part of the distribution data is indicated by hatching, and the undownloaded part (unreceived part and missing part) due to missing or the like is shown in white.

Suppose that the distribution data assumed in the partial data download method is data such as moving images and sound data where the part used along the flow of time changes. For this reason, it is assumed that the distribution data is used sequentially from the left part. Therefore, there is a feature that the timing to be used becomes earlier as it goes to the left in FIG. 9, and the timing to be used becomes later as it goes to the right. In the following, after a data usage start instruction (eg, playback instruction) from the user, a portion that is used first (eg, moving image data used immediately after the start of playback) is referred to as “use start data”, and finally The portion used for the video (eg, moving image data used immediately before the completion of reproduction) is referred to as “use end data”. If the use start data has already been acquired, the use start data is already stored in the data storage unit 240 even when the user gives an instruction to use the distribution data. You can start using it. Therefore, it can be said that the data at the start of use is highly effective in obtaining in advance (acquisition prior to user use). On the other hand, for data at the end of use, even if the download is started after the user has instructed the use of distribution data, the data restoration may be in time, so the effect of pre-acquisition is relatively low. FIG. 9 shows an example in which the top portion of the distribution data including the use start data is pre-acquired data, and an example in which an unreceived portion exists in the pre-acquired data.

FIG. 10 is a flowchart showing a processing flow in the partial data download method. FIG. 7 shows examples of variable names and their values recorded in the metadata used in this embodiment.

First, the communication control unit 210 of the data receiving terminal 20 acquires metadata (step 401a) and distribution data using multimedia broadcasting (step 402a). The processing of step 401a and step 402a is equivalent to the processing of step 101a and step 102a shown in FIG.

Thereafter, when the determination unit 220 of the data receiving terminal 20 determines that there is a missing portion in the distribution data (step 403a: Yes), next, it is determined whether or not there is an unreceived portion in the pre-acquired data in the distribution data. Judgment is made (step 404a). The size of the unreceived part at this time is indicated by PreDLSize described in the metadata shown in FIG. That is, the determination unit 220 determines whether there is an unreceived portion in the pre-acquired data having the size indicated by PreDLSize in the distribution data. The data distribution server 10 includes information on PreDLSize in the metadata and distributes it to the data receiving terminal 20.

Next, when the determination unit 220 determines that there is an unreceived part in the pre-acquired data (step 404a: Yes), a file restoration procedure is executed for the unreceived part of the pre-acquired data (step 405a). On the other hand, when the determination unit 220 determines that there is no unreceived portion in the pre-acquired data (step 404a: No), the file restoration procedure is not executed and the process proceeds to the next step.

Next, when use is instructed by the user through the input / output control unit 230 such as instructing reproduction of the data (step 406a: Yes), data restoration is started for the remaining missing portion of the distribution data (step 406). 407a). In this step 407a, any one or more of the above-described time-shift download method, data usage status adaptive download method, and data usage status adaptive download method may be applied. On the other hand, when there is no usage instruction from the user (step 406a: No), it waits until there is an instruction.

On the other hand, when the determination unit 220 of the data receiving terminal 20 determines in step 403a that there is no missing portion in the distribution data (step 403a: Yes), the unreceived portion of the pre-acquired data and the missing portion of the distribution data Is not repaired.

FIG. 11 is a sequence diagram for explaining the procedure of the partial data download method described above based on the overall configuration of the data distribution system 1.

Step 501a and step 502a in FIG. 11 are the same as step 101a and step 102a in FIG. However, the data D1 among the data D1, D2, and D3 that are the distribution data is pre-acquired data, and the data receiving terminal 20B has failed to acquire the data D1 and the data D3. B of the data receiving terminal 20 that has failed to receive data thereafter performs the missing part complementation by the file repair procedure (

steps

503a and 504a). In step 503a, since there is an unreceived portion in the pre-acquired data, the data D1 whose reception has failed is complemented by unicast on the mobile communication network. Thereafter, when the user gives an instruction to start using the distribution data, the remaining data D3 is acquired by the file restoration procedure (step 504a).

With the above procedure, the data receiving terminal 20 can distinguish between data (preliminarily acquired data) that should be subjected to the file restoration procedure in advance and data that is not so, and can download only the previously acquired data in advance. .

In the above description, PreDLSize is described in the metadata, and the procedure in which the data distribution server 10 notifies the data receiving terminal 20 has been described. However, the data receiving terminal 20 stores the metadata in which PreDLSize is described in advance. May be. In this case, the determination in step 404a is made based on the PreDLSize described in the metadata stored in advance in the data storage unit 240 of the data receiving terminal 20.

(PreDLSize determination method: 1)
It is also possible to change the size of the pre-acquired data of the partial data download method according to the situation. Hereinafter, a method for determining the size of the pre-acquired data in the partial data download method will be described.

The reason why the pre-acquired data is set in the data receiving terminal 20 is to prevent the download waiting time for the missing portion from occurring when the user starts using the distribution data. Therefore, it is preferable to calculate the size of the pre-acquired data so that all missing portions can be complemented before the reproduction of the distribution data is completed.

Here, the size of the pre-acquired data is x (= PreDLSize), the total length (total size) of the distribution data is D, the reproduction time of the distribution data is T, and the average bit rate of the unicast communication network in the communication wave transmission / reception function is V. Assuming that all parts other than the pre-acquired data are missing, the size is (Dx). Therefore, assuming that all parts other than the pre-acquired data are missing, the download time can be calculated by (D−x) / V. If x can be obtained so that the download time becomes shorter than the data reproduction time T, it is possible to complement all the missing portions before the data reproduction is completed. If this is expressed in mathematical formulas,
x = D-TV (4)
(However, x satisfying 0 ≦ x ≦ D)
become.

In the following, the above formulas will be described with specific examples. For example, in a situation where data of 2 Mbytes is downloaded over a 100 Kbps network with a playback time of 80 seconds, 1 Mbyte can be determined as the size of pre-acquired data (= PreDLSize).

In addition, since the case where all the parts other than the pre-acquired data are missing is assumed to be the worst case, if x is calculated so as to satisfy the above-described calculation formula, all the data will be It will be possible to complement.

(PreDLSize determination method: 2)
In the above-described data usage situation adaptive download method, the calculation is based on the past received data usage rate p as a parameter representing the probability that the data is actually used and the communication costs C1, C2, C3, and C4 required when using communication. Whether or not to execute the file restoration procedure was determined using the relationship between the threshold value Z of the utilization rate thus determined and the determination criterion. However, whether or not the distribution data is used may differ depending on the portion of the distribution data. Considering this point, it can be considered that the determination regarding the execution of the file repair procedure can be made more accurately. In addition, as an example in which the utilization rate differs for each part of the distribution data, for example, in FIG. 9 described above, the probability that the use start data is referred to by the user in order to confirm the content of the distribution data However, the data at the end of use is considered to have a high probability of not being used because the data content does not match the user's intention.

The method for determining the size of the pre-acquired data described below is a determination method that focuses on the point that the use probability of the distribution data differs for each part of the data. That is, the size of the pre-acquired data is the past received data partial usage rate calculated based on the usage history in each part of the past received data that is data received in the past from the data distribution server 10 (probability of data usage probability described later). It is calculated based on the density function. Specifically, the total size of each part whose past received data part usage rate is equal to or greater than a predetermined threshold is calculated as the size of the pre-acquired data. Hereinafter, a method for determining the size of the pre-acquired data based on the past received data partial utilization rate will be described with reference to a specific example.

FIG. 12 and FIG. 13 show examples in which the use probabilities differ for each part of the distribution data. Graphs G1 and G2 are probability density functions of use probability of distribution data. FIG. 12 shows that the top portion of data (use start time data) has a high use probability, and conversely the second half of data (use end data) has a low use probability. FIG. 12 is merely an example, but on average, it can be said that the transition is generally performed with the use probability as shown in FIG. However, as an exception, as shown in FIG. 13, for example, in the case of a moving image of a sports program, the reference probability of a highlight portion such as a goal scene (a portion corresponding to the data size (d3-d2)) is locally Some cases are expensive.

In order to determine the size of the pre-acquired data, the data receiving terminal 20 first obtains a probability density function of the data use probability regarding the past distribution data. The probability density function of the data use probability obtained by the data receiving terminal 20 is expressed as G1 or G2 in FIGS. Next, for example, in FIG. 12, when the expected value of the probability density function is p1, an intersection k1 between the probability density function of the data use probability and the expected value p1 is obtained as shown by a horizontal broken line in FIG. When the intersection k1 is obtained, the data size d1 corresponding to k1 is obtained. Finally, by setting the data size d1 as the pre-acquired data size PreDLSize, the pre-acquired data size PreDLSize can be determined based on the use probability of the distribution data. Note that the expected value p1 of the probability density function can be set as appropriate in consideration of the communication status, the type of data, the current usage status, and the like.

For example, in FIG. 13, if the expected value of the probability density function is p2, intersections k2 and k3 between the probability density function of the data use probability and the expected value p2 are obtained as shown by the horizontal broken line in FIG. . When the intersection points k2 and k3 are obtained, data sizes d2 and d3 respectively corresponding to the intersection points k2 and k3 are obtained. Finally, by setting the data size (d3-d2) as the pre-acquired data size PreDLSize, the pre-acquired data size PreDLSize can be determined based on the use probability of the distribution data. Note that the expected value p2 of the probability density function can be appropriately set in consideration of the communication status, the type of data, the current usage status, and the like.

By using the above method, it is possible to download in advance the part with a high data use probability as pre-acquired data.

(Combination of each method)
Each method described above, ie, time shift download method, network adaptive download method, data usage adaptive download method, partial data download method, PreDLSize determination method 1 and PreDLSize determination method 2 are combined. It is also possible to use it.

As an aspect of the method combination, for example, FIG. 10 described above shows a processing flow in the partial data download method, and when the determination unit 220 determines in step 404a that there is an unreceived portion in the pre-acquired data, In step 405a, the file repair procedure is executed for the unreceived portion of the pre-acquired data. Here, between step 404a and step 405a, processing such as step 204a in the time shift download method shown in FIG. 6 and step 304a in the network adaptive download method shown in FIG. 8 may be further included. In this way, various combinations other than the combinations described as an example are possible, and the condition (And / Or) of each combination can be included in the metadata.

(Judgment on the data distribution server 10 side)
In the above description, the case where the main body that determines whether or not to repair the missing portion of the distribution data and the unreceived portion of the pre-acquired data is the determination unit 220 of the data receiving terminal 20 has been described. However, the present invention is not limited to this, and the above determination may be performed on the data distribution server 10 side. In this case, the data receiving terminal 20 makes a retransmission request to the missing portion of the distribution data or the unreceived portion of the pre-acquired data without making this determination. Next, when the retransmission request receiving unit 130 of the data distribution server 10 receives a retransmission request from the data receiving terminal 20 using the communication wave transmission / reception function, the retransmission determining unit 140 of the data distribution server 10 performs communication according to the retransmission request. Based on at least one of the situation and the data-related situation, it is determined whether to retransmit the missing portion of the distribution data. The communication status and data related status at this time are as described above.

That is, the communication status at this time includes the relationship between the current time and a preset time zone, the type of network currently available between the data receiving terminal 20 and the data distribution server 10, and the preset network. The relationship between the types of base stations currently available in the currently available network and the types of base stations preset in relation to the currently available network, data reception The relationship between the remaining battery level of the terminal 20 and a preset threshold of the remaining battery level, and the type of network usage contract currently concluded between the data receiving terminal 20 and the data distribution server 10 are set in advance. The relationship between the type of network usage contract and the radio wave intensity between the data receiving terminal 20 and the data distribution server 10 are set in advance. A relationship like between the radio wave intensity threshold.

The data related status at this time represents the usage status of the distribution data, and is calculated based on the past received data usage rate p calculated based on the usage history of the past received data and the communication status described above. It may also be a relationship between the utilization rate threshold Z. In this case, the retransmission determination unit 140 of the data distribution server 10 compares the past received data usage rate p with the usage rate threshold Z, and when the past received data usage rate p is equal to or greater than the threshold Z, the time described above is used. Based on the shift download method or the network adaptive download method, it is determined that the user of the data receiving terminal 20 will repair the missing portion in advance before using the distribution data. Further, the utilization rate threshold Z in this case can be calculated based on the formula (1) or (3) described above.

(Operation and effect of this embodiment)
Then, the effect | action and effect of the data delivery system 1 concerning this embodiment are demonstrated. According to the data distribution system 1 of the present embodiment, when the data receiving terminal 20 determines that there is a missing portion in the distribution data, the communication status between the data receiving terminal 20 and the data distribution server 10 and distribution Based on at least one of the data-related situations that are data-related situations, it is determined whether or not to repair the missing portion. Since it is properly determined whether or not to perform the defect repair process based on the communication status and the data-related status, wasteful communication costs can be reduced when repairing the missing portion in data communication using broadcast waves with a communication wave. It becomes possible not to generate.

Further, according to the present embodiment, the data distribution server 10 communicates between the data receiving terminal 20 and the data distribution server 10 in response to a retransmission request from the data receiving terminal 20 to retransmit the missing portion of the distribution data. Based on at least one of the situation and the data-related situation that is the situation related to the distribution data, it is determined whether or not the missing portion is to be repaired. Since it is properly determined whether or not to perform the defect repair process based on the communication status and the data-related status, wasteful communication costs can be reduced when repairing the missing portion in data communication using broadcast waves with a communication wave. It becomes possible not to generate.

The present invention provides a data receiving terminal, a data distribution server, a data distribution system, and a data distribution method that can prevent useless communication costs when a missing portion in data communication using a broadcast wave is repaired by a communication wave. .

Claims

A data receiving terminal having a broadcast wave receiving function and a communication wave transmitting / receiving function,
Broadcast wave receiving means for receiving data from a data distribution server using the broadcast wave receiving function;
It is determined whether or not there is a missing portion in the data, and when it is determined that there is the missing portion, the communication status between the data receiving terminal and the data distribution server, and the status related to the data Based on at least one of the data-related situations, a repair determination means for determining whether to repair the missing portion;
When the repair determining unit determines to repair the missing part, the communication wave transmission / reception function is used to request the data distribution server to resend the missing part, and the data based on the retransmission request Communication wave transmitting / receiving means for receiving the lost portion transmitted from the distribution server using the communication wave transmitting / receiving function;
Storage means for storing the missing portion received by the communication wave transmitting / receiving means;
A data receiving terminal comprising:
The communication status is a relationship between the current time and a preset time zone,
The repair determination means compares the current time with the time zone, and determines that the missing portion is to be repaired when the current time is within the time zone.
The data receiving terminal according to claim 1.
The communication status is a relationship between a network type currently available between the data receiving terminal and the data distribution server, and a preset network type,
The repair determining means compares the currently available network type with the preset network type, and determines that the missing portion is repaired if there is a match in both types.
The data receiving terminal according to claim 1.
The communication status is a relationship between a type of a base station that is currently available in the currently available network and a type of a base station that is set in advance in association with the currently available network;
The repair determining means compares the currently available base station type with the preset base station type, and determines that the missing portion is to be repaired if there is a match in both types. ,
The data receiving terminal according to claim 3.
The communication status is a relationship between the remaining battery level of the data receiving terminal and a preset remaining battery level threshold,
The repair determining means compares the remaining battery level of the data receiving terminal with the threshold value, and determines that the defective portion is repaired when the remaining battery level of the data receiving terminal is equal to or greater than the threshold value.
The data receiving terminal according to claim 1.
The communication status is a relationship between the type of network usage contract currently concluded between the data receiving terminal and the data distribution server, and a preset type of network usage contract.
The repair determining means compares the type of the currently used network usage contract with the preset type of the network usage contract, and if there is a match between the two types, the missing portion is determined. Decide to repair,
The data receiving terminal according to claim 1.
The communication status is a relationship between the radio wave intensity between the data receiving terminal and the data distribution server, and a preset radio wave intensity threshold,
The repair determination means compares the radio field intensity between the data receiving terminal and the data distribution server with the threshold value, and the radio field intensity between the data receiving terminal and the data distribution server is equal to or greater than the threshold value. If it is determined to repair the missing part,
The data receiving terminal according to claim 1.
The data-related status includes a past received data usage rate calculated based on a usage history of past received data that is data received in the past from the data distribution server, and a usage rate threshold value calculated based on the communication status. The relationship between Z and
The restoration determination means compares the past received data usage rate and the threshold Z of the usage rate, and when the past received data usage rate is equal to or greater than the threshold Z, the user of the data receiving terminal Determining that the defect is repaired prior to use,
The data receiving terminal according to claim 1.
The communication status is a relationship between the current time and a preset time zone,
The utilization threshold Z is
Z = C1 / C2 (1)
(However, C1 is a communication cost when communication is performed by the communication wave transmission / reception function within the preset time zone, and C2 is communication by the communication wave transmission / reception function outside the preset time zone. It is the communication cost when going.)
Calculated by
The data receiving terminal according to claim 8.
The utilization threshold Z is
Z = (C1 / C2) × W (2)
(W is a weight according to the genre of data transmitted from the data distribution server.)
The data receiving terminal according to claim 9.
The communication status is a relationship between the type of network usage contract currently concluded between the data receiving terminal and the data distribution server, and a preset type of network usage contract.
The utilization threshold Z is
Z = C3 / C4 (3)
(However, C3 is a communication cost when communication is performed by the communication wave transmission / reception function based on the preset network use contract, and C4 is a use contract other than the preset network use contract. This is the communication cost when communication is originally performed by the communication wave transmission / reception function.)
Calculated by
The data receiving terminal according to claim 8.
The broadcast wave receiving means receives pre-acquired data, which is a predetermined part of data received from the data distribution server, from the data distribution server using the broadcast wave reception function,
The data related status is whether or not there is an unreceived part in the pre-acquired data,
The repair determining means determines that the user of the data receiving terminal repairs the unreceived portion prior to using the data when determining that the pre-acquired data includes the unreceived portion;
The data receiving terminal according to claim 1.
The pre-acquired data is a head portion of data received from the data distribution server,
The data receiving terminal according to claim 12, wherein:
The size of the pre-acquired data is
x = D-TV (4)
(Where x is the size of the previously acquired data, D is the total size of the data received from the data distribution server, T is the reproduction time of the data, and V is the network in the communication wave transmission / reception function) The average bit rate of
Calculated by
The data receiving terminal according to claim 12, wherein:
The size of the pre-acquired data is calculated based on a past received data partial usage rate calculated based on a usage history in each part of past received data that is data received in the past from the data distribution server,
The total size of each part in which the past received data part usage rate is equal to or greater than a predetermined threshold is calculated as the size of the pre-acquired data;
The data receiving terminal according to claim 12, wherein:
The broadcast wave receiving means receives metadata describing at least one of the communication status and the data-related status from the data distribution server using the broadcast wave receiving function.
The data receiving terminal according to claim 1.
The storage means stores metadata describing at least one of the communication status and the data-related status.
The data receiving terminal according to claim 1.
A data distribution server having a broadcast wave transmission function and a communication wave transmission / reception function,
Data transmitting means for transmitting data to a data receiving terminal using the broadcast wave transmitting function;
Retransmission request receiving means required to retransmit the missing portion of the data from the data receiving terminal using the communication wave transmitting / receiving function;
Based on the retransmission request, the missing portion transmitting means for transmitting the missing portion to the data receiving terminal using the communication wave transmitting / receiving function;
A data distribution server comprising:
In response to the retransmission request, whether or not to retransmit the missing portion based on at least one of a communication status between the data distribution server and the data receiving terminal and a data related status that is a status related to the data Further comprising retransmission judgment means for judging whether
When the retransmission determination unit determines to retransmit the defective part, the defective part transmission unit transmits the defective part to the data receiving terminal using the communication wave transmission / reception function.
The data distribution server according to claim 18.
The data related status is calculated based on the past received data usage rate calculated based on the usage history of past received data that is data received in the past from the data distribution server by the data receiving terminal and the communication status. The relationship between the utilization rate threshold Z and
The retransmission judging means compares the past received data usage rate with the usage rate threshold Z, and if the past received data usage rate is equal to or greater than the threshold Z, the user of the data receiving terminal Determining to retransmit the missing portion to the data receiving terminal prior to use;
The data distribution server according to claim 19.
The communication status is a relationship between the current time and a preset time zone,
The utilization threshold Z is
Z = C1 / C2 (1)
(However, C1 is a communication cost when communication is performed by the communication wave transmission / reception function within the preset time zone, and C2 is communication by the communication wave transmission / reception function outside the preset time zone. It is the communication cost when going.)
Calculated by
The data distribution server according to claim 20, wherein the data distribution server is a data distribution server.
The communication status is a relationship between the type of network usage contract currently concluded between the data receiving terminal and the data distribution server, and a preset type of network usage contract.
The utilization threshold Z is
Z = C3 / C4 (3)
(However, C3 is a communication cost when communication is performed by the communication wave transmission / reception function based on the preset network use contract, and C4 is a use contract other than the preset network use contract. This is the communication cost when communication is originally performed by the communication wave transmission / reception function.)
Calculated by
The data distribution server according to claim 20, wherein the data distribution server is a data distribution server.
The data transmitting means transmits metadata describing at least one of the communication status and the data related status to the data receiving terminal using the broadcast wave receiving function.
The data distribution server according to claim 18.
A data distribution system including a data reception terminal having a broadcast wave reception function and a communication wave transmission / reception function, and a data distribution server having a broadcast wave transmission function and a communication wave transmission / reception function,
The data receiving terminal is
Broadcast wave receiving means for receiving data from the data distribution server using the broadcast wave receiving function;
It is determined whether or not there is a missing portion in the data, and when it is determined that there is the missing portion, the communication status between the data receiving terminal and the data distribution server, and the status related to the data Based on at least one of the data-related situations, a repair determination means for determining whether to repair the missing portion;
When the repair determining unit determines to repair the missing part, the communication wave transmission / reception function is used to request the data distribution server to resend the missing part, and the data based on the retransmission request Communication wave transmitting / receiving means for receiving the lost portion transmitted from the distribution server using the communication wave transmitting / receiving function;
Storage means for storing the missing portion received by the communication wave transmitting / receiving means;
With
The data distribution server is
Data transmission means for transmitting the data to the data receiving terminal using the broadcast wave transmission function;
Retransmission request receiving means required to retransmit the missing portion of the data from the data receiving terminal using the communication wave transmitting / receiving function;
Based on the retransmission request, a missing part transmitting means for transmitting the missing part to the data receiving terminal using the communication wave transmitting / receiving function;
A data distribution system comprising:
A data distribution method in a data distribution system including a data receiving terminal having a broadcast wave reception function and a communication wave transmission / reception function, and a data distribution server having a broadcast wave transmission function and a communication wave transmission / reception function,
A data transmission step in which data transmission means of the data distribution server transmits data to the data receiving terminal using the broadcast wave transmission function;
Broadcast wave receiving means for receiving the data from the data distribution server, using the broadcast wave receiving function, the broadcast wave receiving means of the data receiving terminal;
When the data receiving terminal repair determination means determines whether or not there is a missing portion in the data, and determines that there is the missing portion, the communication status between the data receiving terminal and the data distribution server And a repair determination step for determining whether or not to repair the missing portion based on at least one of data-related situations, which is a situation related to the data, and communication wave transmitting / receiving means of the data receiving terminal, A first communication wave transmission / reception step for requesting the data distribution server to retransmit the defective portion using the communication wave transmission / reception function when the repair determination means determines to repair the defective portion;
Retransmission request reception means of the data distribution server is requested to retransmit the missing portion of the data from the data receiving terminal using the communication wave transmission / reception function;
The missing part transmitting means of the data distribution server transmits the missing part to the data receiving terminal using the communication wave transmitting / receiving function based on the retransmission request,
A second communication wave transmission / reception step in which the communication wave transmission / reception means of the data receiving terminal receives the lost portion transmitted from the data distribution server based on the retransmission request using the communication wave transmission / reception function;
A storage step in which the storage means of the data receiving terminal stores the missing portion received by the communication wave transmitting / receiving means; and
A data distribution method characterized by the above.
The communication status is a relationship between the current time and a preset time zone,
The repair determination means compares the current time with the time zone, and determines that the missing portion is to be repaired when the current time is within the time zone.
26. The data distribution method according to claim 25.
The communication status is a relationship between a network type currently available between the data receiving terminal and the data distribution server, and a preset network type,
The repair determining means compares the currently available network type with the preset network type, and determines that the missing portion is repaired if there is a match in both types.
26. The data distribution method according to claim 25.
The communication status is a relationship between a type of a base station that is currently available in the currently available network and a type of a base station that is set in advance in association with the currently available network;
The repair determining means compares the currently available base station type with the preset base station type, and determines that the missing portion is to be repaired if there is a match in both types. ,
28. The data distribution method according to claim 27.
The communication status is a relationship between the remaining battery level of the data receiving terminal and a preset remaining battery level threshold,
The repair determining means compares the remaining battery level of the data receiving terminal with the threshold value, and determines that the defective portion is repaired when the remaining battery level of the data receiving terminal is equal to or greater than the threshold value.
26. The data distribution method according to claim 25.
The communication status is a relationship between the type of network usage contract currently concluded between the data receiving terminal and the data distribution server, and a preset type of network usage contract.
The repair determining means compares the type of the currently used network usage contract with the preset type of the network usage contract, and if there is a match between the two types, the missing portion is determined. Decide to repair,
26. The data distribution method according to claim 25.
The communication status is a relationship between the radio wave intensity between the data receiving terminal and the data distribution server, and a preset radio wave intensity threshold,
The repair determination means compares the radio field intensity between the data receiving terminal and the data distribution server with the threshold value, and the radio field intensity between the data receiving terminal and the data distribution server is equal to or greater than the threshold value. If it is determined to repair the missing part,
26. The data distribution method according to claim 25.
The data-related status includes a past received data usage rate calculated based on a usage history of past received data that is data received in the past from the data distribution server, and a usage rate threshold value calculated based on the communication status. The relationship between Z and
The restoration determination means compares the past received data usage rate and the threshold Z of the usage rate, and when the past received data usage rate is equal to or greater than the threshold Z, the user of the data receiving terminal Determining that the defect is repaired prior to use,
26. The data distribution method according to claim 25.
The communication status is a relationship between the current time and a preset time zone,
The utilization threshold Z is
Z = C1 / C2 (1)
(However, C1 is a communication cost when communication is performed by the communication wave transmission / reception function within the preset time zone, and C2 is communication by the communication wave transmission / reception function outside the preset time zone. It is the communication cost when going.)
Calculated by
33. A data distribution method according to claim 32, wherein:
The utilization threshold Z is
Z = (C1 / C2) × W (2)
(W is a weight according to the genre of data transmitted from the data distribution server.)
34. The data distribution method according to claim 33.
The communication status is a relationship between the type of network usage contract currently concluded between the data receiving terminal and the data distribution server, and a preset type of network usage contract.
The utilization threshold Z is
Z = C3 / C4 (3)
(However, C3 is a communication cost when communication is performed by the communication wave transmission / reception function based on the preset network use contract, and C4 is a use contract other than the preset network use contract. This is the communication cost when communication is originally performed by the communication wave transmission / reception function.)
Calculated by
33. A data distribution method according to claim 32, wherein:
The broadcast wave receiving means receives pre-acquired data, which is a predetermined part of data received from the data distribution server, from the data distribution server using the broadcast wave reception function,
The data related status is whether or not there is an unreceived part in the pre-acquired data,
The repair determining means determines that the user of the data receiving terminal repairs the unreceived portion prior to using the data when determining that the pre-acquired data includes the unreceived portion;
26. The data distribution method according to claim 25.
The pre-acquired data is a head portion of data received from the data distribution server,
The data distribution method according to claim 36, wherein:
The size of the pre-acquired data is
x = D-TV (4)
(Where x is the size of the previously acquired data, D is the total size of the data received from the data distribution server, T is the reproduction time of the data, and V is the network in the communication wave transmission / reception function) The average bit rate of
Calculated by
The data distribution method according to claim 36, wherein:
The size of the pre-acquired data is calculated based on a past received data partial usage rate calculated based on a usage history in each part of past received data that is data received in the past from the data distribution server,
The total size of each part in which the past received data part usage rate is equal to or greater than a predetermined threshold is calculated as the size of the pre-acquired data;
The data distribution method according to claim 36, wherein:
The broadcast wave receiving means receives metadata describing at least one of the communication status and the data-related status from the data distribution server using the broadcast wave receiving function.
26. The data distribution method according to claim 25.
The storage means stores metadata describing at least one of the communication status and the data-related status.
26. The data distribution method according to claim 25.